Certain electrical connectors are mountable to panels such as housings of electronic apparatus such as computer terminals, extending through panel cutouts such as at an input/output ports. Such connectors are to be mated to mating connectors on one side of the panel, with mating arrays of terminals thereof to become electrically engaged along connector mating faces, and having their terminals connected on the other side of the panel such as to a plurality of conductors of a printed circuit board or to wires along a wire receiving face. Where a plurality of similar such connectors are mounted in an array to a panel, for mating to a like plurality of mating connectors, the connectors must be labeled or otherwise visibly marked to indicate which of the mating connectors all similar in appearance and shape, are to mate with which of the mounted connectors all similar in appearance and shape.
It would be desirable to provide a means to mechanically prevent all but the particular mating connector from being mated to a particular mounted connector. Types of connectors are known in which cooperating keying structures are utilized which are shaped and positioned and correspondingly oriented along the respective mating faces of the pair of connectors to allow mating when the two connectors matchingly keyed are being moved axially together, but abut and physically obstruct mating when two connectors are being moved together which are not matchingly keyed.
Such keys are usually used in pairs matable with corresponding pairs and usually have body sections which are hexagonal or octagonal in cross-sectional shape, and the keys of each pair are secured to a respective one of the connectors with their body sections in apertures of the connector housing which are correspondingly shaped in cross-section; thus each key can be secured in its respective aperture in any one of six or eight different positions. Each key includes a keying projection extending axially forwardly from the octagonal body section but only extending around one half of the circumference; the corresponding key will have a keying projection which will enter the region comprising the other one half of the circumference, when the two connectors which are matchingly keyed are moved axially together. By coordinating the selection of positions of the two keys of each connector of the pair desired to be matable, the keys provide a means for physically encoding the mating faces of the pair of connectors.
In one type of panel-mountable connector and matable connector, one of them includes a forward plug section of the terminal housing which is D-shaped in transverse cross-section to be received in a cavity of the other upon mating, with the cavity being correspondingly D-shaped. Each of the housings is secured within metal front and rear shell members each of which is stamped and drawn or stamped and formed, defining a central housing-receiving cavity within which the dielectric housing is placed, after which the shells are secured to each other thus holding the housing therewithin. The front and rear shells include flanges extending transversely outwardly from the housing-receiving cavity to abut a transverse surface of the panel to which the panel-mountable connector is to be mounted, surrounding the panel cutout, and including a pair of lateral flange sections including apertures through which extend mounting fasteners such as mounting screws to hold the connector to the panel. The front shell of one of the matable pair of connectors includes a forwardly extending hood section which comprises the D-shaped plug-receiving cavity; the front shell of the other connector also has a D-shaped forwardly extending section slightly smaller to be receivable into the cavity, and which contains the housing's plug section.
One such pair of connectors is a product sold by AMP Incorporated under Part Nos. 208743-1 and 208552-1. In the AMP product the front and rear shells are secured together by a pair of small tabs extending outwardly from the edge of each lateral flange section of one of the shells being bent around the corresponding flange section of the other shell so that the shell members are clinched together at each end.
It is desired to provide keying for a mating pair of shielded connectors one of which is mountable to a panel, where the key or keys do not occupy any of the space across the mating face of the connectors, which is desired to be occupied only by contact sections of matable terminals of the connectors.